The present invention relates to a method of and apparatus for conditioning a traveling textile fabric substrate during temporary change-over discontinuance of treating liquor application in a textile treating and drying range, and more particularly to such a method and apparatus applicable to allow cleaning of liquor from a liquor applicator during a batch change.
Textile fabric treating and drying ranges to which the present invention is applicable conventionally use a dyeing padder or other liquor applicator such as a spray applicator, a foam applicator or a low liquor-ratio applicator followed by a drying oven and/or an infrared preliminary dryer. When there is a batch change, particularly a dye change, it is necessary that the liquor be cleaned from the applicator. This is usually done by first draining the previous liquor from the container of the applicator, such as in a dye back, and replacing the liquor with clear water for cleaning the container, the guide rollers and the squeeze roll unit as well as any other associated components. The guide rollers can also be sprayed and later dried. Usually a cloth lead is sewn to the end of the previously treated fabric substrate and is drawn through the cleaning material. As the cloth lead that has been drawn through the cleaning material is at least as wet as the fabric substrate during the normal treating operation, there is usually no risk of damage to the substrates by allowing the dryer to continue in operation at the normal operating temperature condition.
It is desirable during temporary interruptions of operation that the dryer continue to operate at normal operating temperature because if it is turned off during a batch change and subsequently turned back on, there is a delay required before a steady-state condition is achieved and proper processing results are not obtained during the period of heating to operating temperature. However, during the cleaning of liquor applicators, the equipment must be dried to be sure that all the previous liquor is removed before the applicator and associated container is filled with the new liquor. During this cleaning, an infrared dryer or hot air dryer cannot be allowed to remain at operating temperature as the cloth lead, which is now dry because the applicator is dry, would burn or be damaged from the heat. Dryers can be constructed so that they can be manipulated to direct the heat away from the cloth lead to avoid heat damage, and by-pass passages can be provided to divert hot air away from the fabric, but such solutions require complicated and expensive equipment.